Study On Characteristic And Simulation Of HCU For Regenerative Braking System

The hydraulic control unit(HCU) for regenerative braking system is developed from theHCU for traditional vehicle. The function of the HCU is cooperated with motor braking eachother to recover braking energy in maximum degree on the premise of ensuring brakingsafety, to improve the car’s economy. At present, it has been widely used in the pure electricvehicles and hybrid electric vehicles. In the process of braking energy recovery, due to theintervention of the motor brake, wheel cylinder pressure is no longer solely determined bythe master cylinder pressure, but is jointly determined by the master cylinder pressure andthe motor braking torque. Motor braking torque is influenced by the various conditions ofthe car driving, battery SOC, the driver braking intention. In the process of braking, thevalue of motor braking torque is constantly changing. Therefore, HCU must be able to adjustthe pressure of the wheel cylinder in a short period of time to adapt to changes in the motorbraking torque.Many foreign auto parts companies, such as Bosch and Continental, Ameraca TRW andDelphi, have been studying the HCU for regenerative braking system, and correspondingproducts have been applied to different hybrids and pure electric vehicles.Domestic study ofHCU for traditional automotive braking system is still not deep enough, so the research ofthe HCU for regenerative braking system is only in the theoretical research and trialproduction stage. Carrying on this research has significant meanings for breaking theoverseas technical monopoly and enhancing the independent innovation ability. This articleunifying FAW Technology Center project carried out main contents as follows:1.Theoretical analysis on the HCU for regenerative braking system. It mainly includesthe analysis on structure mechanism and operating mechanism of the hydraulic control unit;the analysis on on-off mechanism of solenoid valve and the realization of linear increasing ofwheel pressure; the analysis on the operating principle of electric hydraulic pump. The aboveresearches provide important theory basis for research on experimental study and modelinganalysis on the HCU.2.Experimental analysis on the HCU for regenerative braking system. It mainly includes the electrical response characteristic test of motor, inlet valve and delivery valve;the increasing of wheel pressure response characteristic test of inlet valve; the dumping ofwheel pressure response characteristic test of delivery valve.The aboveresearches provide important experimental basis for modeling analysis on the HCU.3. Establish the solenoid model of linear solenoid valve, analysis the influence ofstructure parameters on the magnetic properties, and match design for solenoid model basedon the characteristics of the studied system.4. Establish the hydraulic model of HCU, analysis the influence of structure parameterson the hydraulic properties, and match design for HCU.